Flash ignition and safety control



6, 1949 A. F. CRAVER ETAL 2,490,729

FLASH IGNITION AND SAFETY CONTROL SYSTEM FOR GASEOUS FUEL BURNERS FiledJune 29, 1945 5 Sheets-Sheet 1 W Y. INVENTORS 5 7 63 4 SEPT r. CAA 145/?J: 6 4 505 V/XLH? 54 55 3/ V 2/ BY A TTORNE Y 1949 A. F. CRAVER ETAL2,490,729

FLASH IGNITION AND SAFETY CONTROL SYSTEM FOR GASEOUS FUEL BURNERS FiledJune 29, 1945 5 Sheets-Sheet 2 4 1 z a a INVENTORS.

5u F V/XLEE 55 BY K" g 4 ATTORNEY A. F. CRAVER ETAL 2,490,729 FLASHIGNITION AND SAFETY CONTROL SYSTEM FOR GASEOUS FUEL BURNERS 5Sheets-Sheet 3 Dec. 6, 1949 Filed June 29, 1945 ATTORNEY 1949 A. F.CRAVER ET Al- 2,490,729

- FLASH IGNITION AND SAFETY CONTROL SYSTEM FOR GASEOUS FUEL BURNERSFiled June 29, 1945 5 Sheets-Sheet 4 INVENTORS ALB/F7537 F CPA V578 AT7'OP/VE V 1949 A. F. CRAVER ETAL FLASH IGNITION AND SAFETY CONTROLSYSTEM FOR GASEOUS FUEL BURNERS 5 Sheets-Sheet 5 Filed June 29, 1945INVENTORS. ALBERT F CRAVER9 551/5 F V/XLEE A TTOENEY Patented Des:o 6,1949- FLASH IGNITION AND sm'rr CONTROL SYSTEM FOR GASEOUS FUELBURNEBSAlbert F. Graver, Bay Village, and Lcslie r; vizier,

Cleveland, Ohio, assignors to The Patrol Valve ggilnpany, Cleveland,Ohio, a corporation of Application June 29, 1945, SerialN'o. ceasesClaims. (01. 158-4174) Our invention relates to gaseous-fuel burnerignition and concerns both safety fuel-valve control systems andautomatic fuel-valve control systems.

- For the purpose of enabling gaseous iuel'equipment such as kitchenranges, for example, to

be ignited automatically when the 'gasis turned on to a main burner,pilot lights'have been employed. In order to ignite a burner from thepilot flame, tubes known as flash tubes have been the burner to thepilot flame and cause a flame to be flashed back from the pilot throughthe flash tube to the burner for igniting it. A single top pilot hasbeen employed for igniting all of the top range burners on the samelevel by utilizing separate flash tubes extending from the top pilot tothe top burners. Ordinarily, however, a separate and remote pilot and aseparate flash tube have been employed for igniting a remote burner orone at a difierent level such as the oven burner or the broiler burner,for example, where the oven or the broiler burner or the like was to beignited automatically upon opening the gas valve. Since the oven orbroiler burner is at a diflerent level from the top burners in thestandard kitchen range, the automatic ignition of the oven burnerpresents a different problem from the ignition of the top range burnerswhere the top pilot is to be employed for automatic ignition of both.Considerable care is required to guard against flow of unignited gasfrom the oven burner in case of faulty action.

A similar problem is involved in deep-well top burners or any burner fora combustion chamber of a gas burning appliance remote from a pilotflame, or at a diflerent level, including inaccessible enclosed burners.Even if a separate pilot is employed for the oven burner, e. g.,considerable care is required to guard against flow of unignited gasfrom the oven burner in the event that the oven burner pilot should notbe burning.

Accordingly, an object of our invention is to provide improved safeignition systems ior household ranges.

It is also an object of our invention to provide a system for igniting aflame in a combustion ignition m the event. of an flame extinction '10provided which cause gas to be transferred from Another object is toprovide an ignition system for either igniting a main burner or amultiplicity of burners directly or through intermediate burners Afurther object is an ignition system which eliminates danger of gas flowwithout where a single constant burning pilot is required for aplurality of burners to be ignited.

Another object is to provide an ignition system with a plurality ofsupplemental or auxiliary pilot flames in which one flame may be flashedfrom anotherin either direction in the event of extinction of one of theflames.

Still another object is to provide for reduction in flame length ofsupplement pilots after they have accomplished their purpose and toprovide for flow of gas to supplemental pilots only when a main burneris turned on.

Still another object is to prevent through a pilot-flashing tube.

Another object is to prevent concussion within a flash tube and'toprevent interference with propagation of a flash or flame down a flashtube.

Other and iurther objects, features and advantages of the invention willbecome apparent as the description proceeds.

In carrying out the invention in a preferred form thereof, a separateignition pilot is provided for a burner to be ignited such as an oven orbroiler burner, which ignition pilot is adjacent to the oven or broilerburner and which is supplied with gas' only when the oven or broiler gasvalve "is open. An initial flash pilot is provided for igniting theignition pilot, and a flash tube is provided between the flash pilot andthe constant burning conventional top pilot of the range for ignitingthe flash pilot from the top pilot when the oven burner valve is open.

A thermal safety valve control system is provided which is indirectlyresponsive to the 'existence of a flame at the ignition pilot forpreventing the admission of gas to the oven burner or the broiler burneror other burner except when the ignition pilot is burning, and whichserves also to graduate the ignition flash pilot to prevent passingproducts of combustion through the flash tube to the constant burningtop range pilot after the ignition pilot and the oven or broiler burneror other burner have been ignited.

A better understanding of the invention will be aflorded by thefollowing detailed description considered in conjunction with theaccompanyventing g 3 ing drawing. and the scope of the invention will beset forth in the claims appended hereto.

In the drawing:

Fig. 1 is a top plan view. partially in section and with certain partsomitted, of a range having top burners and an oven burner with anignition system in accordance with our invention;

Fig. 2 is a front elevation, partially diagrammatic, of a system forigniting an oven burner in the apparatus of Fig. 1; showing in part awall of the oven;

Fig. 2a is a bottom view of apparatus shown in Fig. 2;

Fig. 3 is a fragmentary top view of a portion of the apparatus of Fig.2, showing the ignition pilot and the initial flash pilot;

Fig. 4 is a side elevation, partially in section and partially distortedfor clarity, showing especially gas lines and controlling arrangements,of the apparatus of Fig. 2 with a part of the apparatus of Fig. 1;

. Fig. 4a is a view of a section of the apparatus represented as out bya broken plane 4a-4a, indicated in Fig. 4.

Fig. 4b is a view of a section of the apparatus represented as cut by a.horizontal plane 4b-4b indicated in Fig. 4.

Fig. 4c is a view of a section of the apparatus represented as cut by ahorizontal plane 4c4c indicated in Fig. 4.

Fig. 5 is a front elevation corresponding to Fig. 2 of a modification ofthe arrangement of Fig. 2;

Fig. 6 is a fragmentary top view of a portion of the apparatus of Fig.5, showing the graduated initial flash pilot and an ignition pilot;

Fig. '7 is a fragmentary side view of the apparatus of Fig. 5illustrating the arrangement of a relay pilot; and

Fig. 8 is a schematic functional diagram of the arrangement of Figs. 1to 4, showing gas lines and valve connections and relation of flashtubes to pilot burners.

Like reference characters are utilized throughout the drawing todesignate like parts.

For the sake of illustration. there is shown in Fig. 1 a household orkitchen range having a plurality of top cooking burners H arranged to beignited by a top pilot burner II. It will be understood that the gratesand a portion of the enclosing walls have been. omitted for the sake ofexposing the piping and burners to view. The range is represented asbeing of the type having a compartment M for an oven or broiler burnerii which will be referred hereinafter for convenience as an oven burner.

For the sake of avoiding confusion in the showing of the oven burner Ii,the range has been shown with all but one of the top burners H omittedand the pilot burner l3 displaced from a normal center position.

For supplying gas to the top burners H and the oven burner IS, a headeror manifold is is provided, having branches with valves l9 interposedfor manually controlling the gas supply to the top burners H, and havinga branch with a valve 2| interposed for manually opening the supply ofgas to the oven burner i5 and to supplemental pilots employed inconnection with the oven burner i5. Preferably, there is a thermostaticvalve 22 for maintaining oven temperature at a pre-set value. A. fixedflame-length pilot burner 23, which will be referred to as an ignitionpilot is provided for igniting the oven burner i5, and a graduated flamepilot burner 24 the top of the stove whereas the burner Ii is within thecompartment 14 below the top of the stove so that the burner i5 and thepilots 23 and 24 are at a lower level thanthe pilot [3 and the burnersll. Consequently, the flash tube 25 extends downwardly from the pilot l3to the pilot 24. For preventing admission of gas to the oven burner l5until after the ignition pilot 23 has been ignited, a safety gas valvecontrol unit 26 is provided which is mounted outside the ovencompartment l4, beyond the insulated oven wall 21 so as to be unaffectedby the heat of the oven compartment l4. As will be explained more indetail hereinafter, the safety device 26 includes a thermal pilot burnercommunicating with the ignition pilot burner 23 through a. substantiallyhorizontal flash tube 28. p

The valve 22 is provided with two outlets supplying a. main line 29 forfeeding gas to the oven burner i5 and a branch line 3i for supplying gasto the various supplemental pilots other than the constantly burningpilot 13. For supplying the constant top pilot [3, a line 32 is providedwhich is taken. directly from the header [8 through an adjusting cook33. Conventional top flash tubes 34 are provided for flashing the topburners II from the constant pilot i3 in the conventional opened. Theoutlet to the main line in such valves is opened and closed by a.thermostatic bellows or the like (not shown) communicating with a bulb50 mounted in the oven space H.

The details of the oven burner igniting system will be more readilyobserved from Figs. 2, 3 and 4. Fig. 2 is primarily a view of the pilotsand flashing arrangements, and Fig. 4 is primarily a view of the gassupply connections, and controls for various pilots and the oven burner.

As shown in Fig. 2 the constant burning top pilot I3 comprises a housing35 enclosing the constant burning pilot jet 36. The flash tube 25 isfitted at the upper end into the housing 35 and extends downward with anopen lower end 31 adjacent the initial flash pilot 24. As shown in Fig.3 the pilot burner 24 has a side port 38 adapted to inject gas into theopen end 31 of the flash tube 25. The flash tube 25 has a vertical arm39 outside the oven wall 21 and a substantially horizontal lateral arm41 extending through an opening 42 in the oven wall 21, from thevertical arm 39 to the flash pilot 24. Preferably, however, the lateralarm 4i is slightly sloping, making an angle of about 10 with thehorizontal as shown, and slopes downward from the vertical arm 39 towardthe flash pilot 24.

The ignition pilot burner 23 has two side ports producing side jets 43and 44. The side jet 43, of a fixed length, extends toward the ovenburner i5 for igniting the jets 45 extending around the oven burner. Thesecond side port of the pilot 23 is for producing the fixed length jet44, or for injecting gas into the horizontal flash tube 28 when the jet44 is for some reason extinguished. The burner 23 is close enough to theburner 24 so that the jets 43 and 44 of the burner 23 are ignited fromthe jet 38 of the burner 24.

The safety valve control unit 28 is preferably mounted outside the ovenwall 21 and may be supported in any suitable manner. By means of a strap46, the vertical arm 38 of the flash tube 25 is located. The safety unit26 includes a head 41 having a side port 48 and a plurality of top ports43 and The side port 43 is located to inject gas into the horizontalflash tube 28 for igniting a jet at the port 48 from the jet 44 of theignition pilot burner 23 or vice versa. The arrangement is such thatjets are ignited at the vertical ports or top ports 48 and 5| from theside jet at the port 48. A temperature-responsive movable member 52,such as a thermostatic bimetal strip, for example, is secured at one endto the safety control unit 26 is such position as to be exposed to theheat of the jets issuing from the top ports 48 and 5|, which thus form athermal pilot burner. The member 52 is provided with a linkage forcontrolling a valve graduating gas supplied to the ports of the unit 26and the ports or the flash pilot 38 as will be explained more in detailhereinafter.

The safety control valve unit 26 as shown in Fig. 4 has two separatepassageways 53 and 53 formed therein. The passageway 53 is connected tothe main gas supply line 23 for the oven burner l5, and the passageway54 is connected to a graduated-pilot supply line 55 for supplying gas tothe ports 48, 49 and 5| of the unit 26 and to the port 38 of the initialflash pilot 24. A main line gas control valve, including a valve disc56,

is formed in the passageway 53, and a pilot may be arranged to abutagainst the main line valve disc 56 and to be resiliently pressedagainst the disc 56 by means of a. biasing spring 6|. Preferably, anadjustable needle valve 62 is also provided in the graduated pilot line.

The branch gas line 3| is branched against a T 63 having one outlet tothe graduated pilot gas supply line 55 and a second outlet to a fixed-flow branch line 64. The fixed flow branch line 64 passes through thehead 41 of the safety unit 26 for support but is not connected theretoand terminates in the ignition pilot burner 23 as shown in Fig. 3.

The inlet to the passageway 54 is from the graduated pilot supply line55, and the passage- W continues past the valve seat 65 cooperating withthe valve disc 57, through a cross passageway 66 beyond the needle valve62 into an upwardly extending portion 61 (shown in Fig. 4a) andcontinues upward in front of the main line passageway 53 as seen in Fig.4, but is not connected thereto, being connected instead to a cavity inthe interior of the head 47 so as to supply gas to the ports 48, 43 and5| and to an outlet gas supply tube 68 shown in Fig. 2. Gas flows to thegraduating pilot 24 through the tube 66.

The valves, including the valve discs '56 and 51 are so constructed andthe arrangement of the thermostatic strip 52 is such that the valve disc56 normally closes the passageway 53 to its outlet 53A when the strip 52is cool, that is when the jets are not burning at the ports 58, E9 and5|, and the valve including the disc 51 is normally open when the strip52 is cool. The

area around the disc 58 is such that as soon as the main line valve isopen a full supply of gas is admitted through the passageway 53 whereasthe construction of the passageway 54 around the disc 51 is such thatmotion of the rods 58 and 53 as the strip 52 varies in temperature has agraduating efiect on the gas admitted through the passageway 54 to theneedle valve 62. I

The inlet to the mainline passageway 53 is from the main gas line 29 andthe outlet is to a continuation 69 forming a part of the main gas linewhich is connected to a mixer 1|, which, in turn, is connected through agas and air mixing tube 12 to the burner 5.

For certain gases it is preferable to supply primary air to the gasdelivered to the initial flash pilot 24, so as to provide a blue-flamepilot having the proper mixture for flashing and not dependent uponsecondary air aspirated around the port. For supplying such primary air,an opening 10 (Fig. 2) is provided in the body of the valve unit 26 andcommunicates with the passageway 61 (Fig. 4).

A domestic range has been described by way of illustration, but it willbe understood that our invention is not limited thereto. The oven burnerI5 is representative of any burner which is to be ignited remotely froma primary pilot, such as the constant burning pilot I 3, or is on adifferent level or is inaccessible or enclosed or for some other reasonnot to be ignited directly like the range top burners In the descriptionand claims a burner which is to be ignited is occasionally referred toas a main burner to distinguish it from the igniting burners such as thepilot burner 24, for example. However, our invention is not limited tocases where the ignited burner is actually the largest burner in theapparatus or the final burner in a chain of successiveignitions;

Before the oven gas cook 2 [is turned on manually, obviously no gas isadmitted to the burner l5, and likewise no gas is admitted to any of thesupplemental pilots such as the pilots 23 and 2 5, and the ports 38, 39and 5| on the head 41 of the safety unit 26, serving as thermal pilots.However, the top pilot I3 is continuously burning and serves as aconstant pilot from which the top burners may be flashed directly or theoven burner |5 may be flashed in directly. When the manual control cock2| is opened, gas is admitted to the oven temperature regulating valve22. Gas is immediately admitted also to the branch line 3| regardless ofoven temperature, and the gas is admitted to the main line 29 inproportion to the extent to which the oven temperature falls below thetemperature for which the regulating valve 22 has been set. Gascontinues to flow into the line 3| as long as the valve 22 is open. Whenthe oven is cold, gas will of course be admitted through the line 29 tothe passageway 53 of the safety unit 26 as far as the valve disc 56. Thedisc 56 is held in the upward position against its seat by thethermostatic strip 52, which is still cold, no thermal pilot jets in thehead 4'! having as yet been ignited. Gas from the line 3| is alsoadmitted to the fixed flow branch line 64 and the pilot graduatingsupply line 55. Gas passing through the fixed supply line 64 admits gasto the ignition burner 23. The line 64 is continuous from the T 63 tothe burner 23, passing through the block d1, but not con-- necting withany chambers therein. Since the strip 52 is still cold, the graduatingvalve including the disc 57 is still fully open admitting a relativellarge supply oi gas from the line 55 through the passageways 54, i4 and41 to the chamber 64 in the thermal pilot head 41. Thence gas passesthrough the graduated pilot line 55 to the initial flash pilot 24. Gasis injected by the port 38 of the pilot 24 into the flash tube 25 andthe gas rises through the upward sloping arm 4| of the flash tube 25 tothe constant pilot housing 35 where it is ignited by the Jet 35, causinga flash back through the tube 25 igniting a jet at the port 38 of theflash pilot 24. The jets at the ports 43 and 44 of the ignition pilot 23are ignited from the flash pilot 24 so that the oven burner could beignited if gas were admitted thereto.

A graduated gas supply through the passageways 54 and 61 also fllls theinterior chamber 60 of the head 41 causing gas to issue from the thermalpilot ports 48, 49 and 5|. The gas issuing from the side port 48 isinjected into the horizontal flash tube 28 and ignited by the side jet44 of the ignition pilot 23. This causes ignition of the remaining jetsin the thermal pilot head 41. The thermostatic strip 52 is then causedto rise in temperature and to open the disc 55 in the main linepassageway admitting gas to the burner |5 and permitting it to beignited from the ignition pilot 23. The operation is indicatedschematically in Fig. 8, where the full-line arrows indicate the passageof flames successively from the top pilot burner |3 to the pilot burners24, 23, 43 and 49. whereupon heating the strip 52 causes the main linesafety valve disc 56 to fall admitting gas to the main burner |5 whichignites from the ignition pilot burner 23.

The heating of the strip 52 also pushes the disc 55 downward upon therod 5! partially closing the valve includin the disc 51 so as to reducethe supply of gas to the head 41 and diminishing the size of the jetsissuing from ports 48 and 49 of the thermal pilot until the strip 52 hascooled sufliciently so that an equilibriuin exists between the size ofthe jets and the opening provided by the position of the graduatingyalve disc 51.

As previously explained, ho ever, the construction of the safety unit 26such that the disc 56 is still far enough away from its seat to admitthe full gas supply to the burner |5. The supply of gas to the initialflash pilot 24 is also grad uated by the graduating valve 51 and,accordingly, the length of flame issuing from the port 38 is shortened.The arrangement is such that initially a relatively long flame isproduced at the port 38 when the thermostatic strip 52 is cool so thatthere is assurance of prompt flashing of the initial flash pilot 24 fromthe constant burning top pilot l3. In order to avoid the continuance ofsuch a long flame which would tend to pass products of combustion upwardthrough the flash tube 25, the flash pilot 24 is supplied by thegraduated line as just explained. Upon the heating of the strip 52 toits equilibrium value causing graduation of the pilot gas supply, theflame issuing from the port 38 is shortened to such an extent that itcurls upward and does not extend into the open end 31 of the flash tube25, and consequently does not introduce any hot air or combustionproducts into the flash tube 25.

space M in a conventional manner. When the oven temperature falls again,since the ignition pilot 23 is normally still burning, the oven burnerI5 is re-ignited by the ignition pilot 23. Gas flows to the pilot 23,through the lines 3| and 54 as long as the valve 22 is open. However, ifthe gas supply should have been turned off by the hand cock 2|, or ifthe ignition pilot 23 should have been extinguished in some other mannerthere would be a danger of the full gas supply issuing from the burner|5 without being ignited except for the presence of the safety featuresprovided. In the event of cutting off of gas through the supply line 3|,gas cannot issue from the burner l5. Cutting oil the supply through theline 3| would, of course. cut oil gas also to the thermal pilots at thehead 41. of the safety unit 26, causing the strip 52 to cool oil, and toclose the main-line passageway 53.

In case the line 3| should remain open but the pilots 23 and 24 shouldbe blown out, they will be re-ignited either from the constant burningpilot 35 or the jet issuing from the side port 48 in the head 41 of thesafety unit 26. If for any reason the constant pilot 35 should have beenblown out or extinguished, the ignition pilot 23 may be ignited from theflames in the ports of the head 41 of the safety unit 26 so that thesafety unit 26 cannot have its bi-metallic control strip 52 heatedwithout causing ignition of the ignition pilot 23 and the burner l5.This is represented by the dotted arrows in the flash tube 28 in Fig. 8.Thus the flash tube 28 provides for flashing in either directiondepending upon which end of the flash tube has a gas jet burning.Consequently, there is no danger of gas supply being admitted to burner|5 without ignition of the gas no matter which one of the various pilotlights may inadvertently become extinguished or may not be lighted.

If the hot air in the oven compartment |4 should have any tendency topass upward through the flash tube 25 and should cause any delay in theflashing of the flamedownward from the constant pilot 3 to the initialflash pilot 24 when the thermostatic valve 22is re-opened after havingbeen closed, there is no danger of gas supply being admitted to theburner I5, because in this case the thermal pilot jets issuing from head41 of the safety unit 26 do not become ignited and heat the bi-metallicstrip 52. Nevertheless, if desired, a relay pilot 13 may be provided asillustrated in Figs. 5 and 7 in order to'increase the speed of operationof the flash tube and also in order to eliminate any possible tendencyfor hot air in the oven compartment M to vent into the pilot housing 35of the constant burning top pilot l3.

In the arrangement of Figs. 5, 6 and 7 the single piece oven flash tube25 represented in Figs. 1 and 2 is replaced by an oven flash-tube systemcomprising a vertical arm flush-tube 14. having an open lower end towhich a flared downwardly extending hood 15 is connected. The upper endof the vertical arm flash tube 14 is bent over horizontally as in thearrangement of Fig. 2 for connection ,to the top pilot housing 35. Thesubstantially horizontal slightly sloping lateral arm 4| of the singlepiece oven flash tube 25 shown in Figs. 1 and 2 is replaced in theembodiments of Figs. 5 and '1 by a separate transverse or lateral flashtube 16 extending from the flash pilot 24 to the hood 15, which has aside opening therein 11, to receive the outer end-oi the flash tube 15as illustrated in Fig. 7. The relay pilot 13 is mounted with an upwardlyopen port 18 slightly above the level of the lower edge 19 of the flaredhood or open mouth 15 at the bottom of the vertical arm flash tube 14.Thus anopen relief space BI is provided around the relay pilot 13. Thevertical arm flash tube 14 is so positioned that it and the hood 14 arelocated on the outer side of a shield plate 82, which is in turn at theouter side of the safety control valve unit 26. The relay pilot isconnected to an aperture in the head 41 of the safety unit 26.

Assuming that the oven burner I is originally turned off, and that thethermostatic strip 52 is cold, as soon as the thermostatic valve 22admits as to the sup ly lines 29 and 3|, gas is admitted to thegraduated pilot line 55 and the graduating valve of the unit 26 to therelay pilot '3 as well as to the initial flash pilot 24 and the ports inthe head 41 'of the safety control unit 26. Gas issuing from the port 18is injected into the hood I5 and the vertical arm flash tube 14 to theconstant burning top pilot housing 35 and ignited from the jet 36. Freshair for producing a combustible mixture is introduced through the open sace 8| into the tube I4. Consequently, the flashing of the flame fromthe jet 36 to the port 18 takes place uniformly unailected by thetemperature of the air within the oven compartment H; The compressionwave of the flash-back is relieved. After the relay pilot 13 has beenignited the flame is flashed back .from it through the flash tube 16 tothe initial flash pilot 24 which ignites the ignition pilot 23.Remaining operations take place as in the case of the apparatus of Figs.1 to 4. Since the mouth 8! of the hood at the lower end of the verticalarm flash tube T8 is open, a relief space is provided for overcoming acompression wave and no delay is caused in the flash back from the jet36 to the port 18. Thus the heat of any air within the compartment l4does not cause a counter current blocking the downward motion of a flashfrom the constant pilot l5 to the relay pilot l3.

We have herein shown and particularly described certain embodiments ofour invention and certain methods of operation embraced therein for thepurpose of explaining its principle of operation and showing itsapplication but it will be obvious to those skilled in the art that manymodifications and variations are possible and we aim, therefore, tocover all such modifications and variations as fall within the scope ofour invention which is defined in the appended claims.

What is claimed is:

1. In combination a top pilot burner, an oven burner to be ignited, anoven burner ignition pilot burner adjacent the oven burner, a graduatdinitial flash pilot burner adjacent the ignition pilot burner, flashtubing from said initial flash pilot burner to said top pilot burner forigniting the initial flash pilot burner from the top pilot burner, asource of gas with a main line for supplying the oven burner, an outletparalleling the main line for supplying the ignition pilot burner whenthe main line is supplying gas, a pilot line for supplying the graduatedpilot burner, and a pilot thermal-responsive safety control meanscomprising a normally closed valve interposed in said even line forcutting off gas except when the ignition pilot burner is burning and anormally open graduating valve interposed in said pilot line for cuttingdown the initial flash pilot flame when the ignition pilot burner isignited.

2. In combination, a constant pilot burner, a main burner to be ignited,an ignition pilot burner adjacent the main burner, a graduated initialflash pilot burner adjacent the ignition pilot burner, flash tubing fromsaid initial flash pilot burner to said constant pilot burner forigniting the initial flash pilot burner from the constant pilot burner,a thermal pilot burner apart from said main burner, a temperatureresponsive movable member in thermal relation to said thermal pilotburner. a main gas supply line, an outlet paralleling said line forsupplying gas to the ignition pilot when the main line is supplying gas.a pilot gas line for supplying the initial flash pilot burner and thethermal pilot burner, a normally closed valve interposed in said mainline and a normally open graduating valve interposed in said pilot line,said valves being mechanically connected in controlled relation to saidtemperature responsive member for respectively opening the normallycolsed valve and reducin the opening of the graduating valve when thetemperature responsive member is heated by said thermal pilot burner.

3. In combination a constant pilot burner, a main burner to be ignited.an ignition pilot burner adjacent the main burner. a graduated initialflash pilot burner adjacent the i nition pilot burner. flash tubing fromsaid initial flash pilot burner to said constant pilot burner for initing the initial flash pilot burner from the constant pilot burner. amain gas supplv line for the main burner, a line for supplying the inition pilot burner, a pilot line for supplying the initial flash pilot.and a pilot-responsive safety control comprising a normally closed valveinterposed in said main gas line for cutting oil gas except when theignition pilot burner is burning and a normally open graduating valveinterposed in said pilot line for cutting down the initial flash pilotflame when the ignition pilot burner is ignited.

4. In combination a constant pilot burner, a main burner to be ignited.an ignition pilot burner adjacent the main burner. a graduated initialflash pilot burner adjacent the ignition ilot burner. a relay pilot atsubstantially the level of the initial flash pilot burner, asubstantially horizontal flash tube from the initial flash pilot burnerto said relay pilot burner and a vertically rising flash tube from therelay pilot burner to the constant pilot burner for igniting the initialflash pilot burner from the constant pilot burner through the relaypilot burner, a main gas supply line for the main burner, a line forsupplying the ignition pilot burner, a pilot burner line for supplyingthe initial flash pilot burner and the relay pilot burner, and a pilotburner responsive safety control comprising a normally closed valveinterposed in said main gas line for cutting ofi gas except when theignition pilot is burning, a normally open graduating valve interposedin said pilot line for cutting down the initial flash flame and therelay pilot burner flame when the ignition pilot burner is burning, andtemperature responsive movable means connected to said valves foractuating them, said means being exposed to flame heat of gas suppliedthrough said graduating valve, whereby burning of such gas results inheat which moves the normally closed valve open and moves the graduatingvalve away from fully open position such gas supplied through the pilotline and gas supplied to the ignition pilot burner through its I! linenormally burning simultaneously, one being ignited from the other.

5. In combination, a constant pilot burner, a main burner to be ignited,an ignition pilot burner adjacent to the main burner, an initial flashpilot burner adjacent to the ignition pilot burner, a relay pilot burnerat substantially the level of the initial flash pilot burner, asubstantially horizontal flash tube from the initial iiash pilot burnerto said relay pilot burner and a vertically rising flash tube from therelay pilot burner to the constant pilot burner through the relay pilotburner, a main gas supply line for the main burner, a line for supplyingthe ignition pilot burner, a pilot line for supplying the initial flashpilot and relay pilot burner, and a pilot responsive safety controlcomprising a normally closed valve interposed in said gas line forcutting oil gas except when the ignition pilot is burning and a normallyopen graduating valve interposed in said gas line for cutting down theinitial flash pilot frame and relay'pilot flame when the ignition pilotburner is ignited.

ALBERT 1". CRAVER. mam: l". VIE-ER.

12 aura-names crrnp The following references are of record in the fileof this patent:

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